Republicans are accidentally doing more to advance progressive values than Democrats

Something strange and unfamiliar has taken root in Washington, DC these past few days. In between segments about Donald Trump’s latest impeachable offense, Republican intransigence in the face of a cataclysmic government shutdown, and whatever other mundanity du jour is on the docket, cable news shows have carved out time to talk about honest-to-God policy proposals.

Specifically, we find ourselves amidst a nationwide conversation about, of all things, marginal tax rates. How we go...